The new 55-inch and 65-inch displays go for a suggested retail price of $5,999.99 and $7,999.99, respectively. LG's current 84-inch model is priced at $19,999.

"We're starting to move Ultra HD into the mainstream with more affordable price points and screen sizes that fit into most homes," says John Taylor, LG's vice president for public affairs and communications.

Also set to enter the Ultra HD derby next month is Sharp's new 70-inch Aquos Ultra HD LED TV ($7,999.99). This first Ultra HD display from Sharp boasts the first THX 4K certification (see a video about the set on Sharp's YouTube channel).

What buyers get from Ultra HD, sometimes referred to as Ultra HD 4K, is four times the resolution of current HD displays. "As screen sizes get larger and as consumers buy larger and larger screens," Taylor says, "they are going to demand more resolution."

Ultra HD sets will upscale current high definition programming â?? on broadcast TV and Blu-ray Discs -- to higher resolutions. And Hollywood is looking at providing movies and TV series in Ultra HD quality.

"Ultra HD TV also provides greater depth to picture quality, giving a more immersive experience," says Sweta Dash, senior director of display research and strategy at research firm IHS. " And with upscaling technology, consumers can see better picture quality even when watching (current) HD content. Learning from past experience, many TV brands are actively working to provide Ultra HD content, either through upscaling or through the creation of proprietary UHD content."

Japan plans to begin Ultra HD broadcast as early as next year, Dash says. "Also, 4K cameras and camcorders are now on the market, enabling creation of 4K content. Movies in 4K are likewise starting to show up."

Next week, Sony begins selling its $699 4K Ultra HD Media Player that will come pre-loaded with 10 4K films and will connect to Sony's Video Unlimited 4K download service. That service, which will offer 24-hour film rental downloads priced from $7.99-$29.99, is set to open in early fall.

Sony currently has on the market an 84-inch Ultra HD set that retails for $24,999.99 and 55-inch and 65-inch models that start at $4,999.99 and $6,999.99, respectively.

LG's new sets have a motorized 50-watt sound bar that can stay hidden or slide down to rest below the screen while you are watching. The sets are the first in this size category to have full-array backlit LED models that deliver better contrast and deeper colors, LG says, and in-plane switching technology allows for better control of separate sections of the array, leading to a more uniform picture.

The new LG sets began selling at Video & Audio Center in Los Angeles, which also was the first to sell LG's initial Ultra HD set and Sony's latest displays. Other specialty electronics retailers will begin offering the sets in the coming weeks.